Well i'm not using Fedora anymore, Ubuntu has replaced it forever :) But i found that Fedora cames with the option exec-shield-randomize enabled,so your stack address change every time you run a program.

For example:

$ gcc -Wall -g --static -o stackp stackp.c$ for i in 1 2 3 4 5; do ./stackp; done&sp is 0xbffff234&sp is 0xbffff134&sp is 0xbffff034&sp is 0xbfffef34&sp is 0xbfffee34

Now if you want to disable the randomization you have to execute this command:

echo 0 > /proc/sys/kernel/exec-shield-randomize

And now if we do the test again, we see that our address is not changing anymore:

$ gcc -Wall -g --static -o stackp stackp.c$ for i in 1 2 3 4 5; do ./stackp; done&sp is 0xbffff234&sp is 0xbffff234&sp is 0xbffff234&sp is 0xbffff234&sp is 0xbffff234